Where did the croatian people come from before coming to Croatia?

There are two main theories about the origin of the Croatian people:

1. The first theory, known as the "Indigenous Theory", suggests that the Croatians are descended from the ancient Illyrian tribes who inhabited the region of Croatia and the surrounding areas of the western Balkans since the Bronze Age. The Indigenous Theory is supported by archaeological, linguistic, and historical evidence, such as the presence of Illyrian hillforts and settlements in Croatia, as well as the similarities between the Croatian language and other Illyrian languages.

2. The second theory, known as the "Migration Theory", proposes that the Croats originated from a region in present-day Poland, known as White Croatia, and migrated to the Balkans during the 6th and 7th centuries AD. According to this theory, the Croats were invited to the region by the Byzantine emperor Heraclius to help defend against the Avars and Slavs. The Migration Theory is primarily based on historical sources, such as the writings of the Byzantine historian Constantine Porphyrogenitus.

It is likely that both theories contain elements of truth, and that the Croatian people are descended from both indigenous Illyrian tribes and migrants from Eastern Europe.